The present invention is directed to thermite compositions, and more particularly to a high- and low-temperature-stable thermite composition for producing high-pressure, high-velocity gases. The Government has rights in this invention pursuant to Contract No. DE-AC04-76DP00053 between the U.S. Department of Energy and Monsanto Research Corporation.
Thermite compositions generally consist of a mixture of a finely divided oxidizable metal and an oxidizing agent therefor. The oxidizing agent typically consists of iron oxide. A highly exothermic reaction takes place when a thermite composition is ignited with the resulting oxidation of the metal and reduction of the iron oxide thereby forming molten iron. Preferably, the oxidizable metal is aluminum, and a wide variety of thermite compositions are known which, in addition to aluminum and iron oxide, contain other modifying agents.
Normally, thermite compositions burn with production of little or no permanent gas. The main use of a thermite composition, therefore, is in the production of extreme heat or molten metal, as previously noted. However, when confined, thermite compositions can produce considerable pressure as a result of momentary vaporization of high-temperature reaction products and expansion of impurities and gases in void spaces. It is therefore desirable in certain applications to enhance the gas production by igniting thermite compositions. Conventionally, this is achieved by adding an easily decomposable material, such as Teflon, that would produce gas upon decomposition and/or reaction. However, these materials often adversely affect the properties of the composition, making it less stable even at relatively low storage temperatures.
Accordingly, there is a need in the art for a thermite composition which is stable at relatively low as well as high temperatures, and which produces high-pressure and high-velocity gases upon ignition.